백금 담지 촉매상에서 에탄올의 저온연소

김문현 ( Moon Hyeon Kim ) 한국환경과학회 2017 한국환경과학회지 Vol.26 No.1

Combustion of ethanol (EtOH) at low temperatures has been studied using titania- and silica-supported platinum nanocrystallites with different sizes in a wide range of 1~25 nm, to see if EtOH can be used as a clean, alternative fuel, i.e., one that does not emit sulfur oxides, fine particulates and nitrogen oxides, and if the combustion flue gas can be used for directly heating the interior of greenhouses. The results of H₂-N₂O titration on the supported Pt catalysts with no calcination indicate a metal dispersion of 0.97±0.1, corresponding to ca. 1.2 nm, while the calcination of 0.65% Pt/SiO₂ at 600 and 900℃ gives the respective sizes of 13.7 and 24.6 nm when using X-ray diffraction technique, as expected. A comparison of EtOH combustion using Pt/TiO₂ and Pt/SiO₂ catalysts with the same metal content, dispersion and nanoparticle size discloses that the former is better at all temperatures up to 200℃, suggesting that some acid sites can play a role for the combustion. There is a noticeable difference in the combustion characteristics of EtOH at 80~200℃ between samples of 0.65% Pt/SiO₂ consisting of different metal particle sizes; the catalyst with larger platinum nanoparticles shows higher intrinsic activity. Besides the formation of CO₂, low-temperature combustion of EtOH can lead to many other pathways that generate undesired byproducts, such as formaldehyde, acetaldehyde, acetic acid, diethyl ether, and ethylene, depending strongly on the catalyst and reaction conditions. A 0.65% Pt/SiO₂ catalyst with a Pt crystallite size of 24.6 nm shows stable performances in EtOH combustion at 120℃ even for 12 h, regardless of the space velocity allowed.

학술발표회 초록 : ( 촉매 및 반응공학 Poster 발표 ) ; Mordenite 형 제올라이트 촉매상에서 탄화수소를 이용한 질소산화물의 선택적 제거에 관한 연구

김문현 (학),남인식 (정),김영걸 (정) ( Moon Hyeon Kim,In Sik Nam,Young Gul Kim ) 한국화학공학회 1992 추계학술발표회 Vol.- No.-

학술발표회 초록 ( 촉매 및 반응공학 (Ⅲ) ) : 구리이온이 교환된 Mordenite 형 촉매상에서 탄화수소에 의한 NO 제거 반응에 대한 SO2 와 H2O 의 영향

김문현 (학),남인식 (정),김영걸 (정) ( Moon Hyeon Kim,In Sik Nam,Young Gul Kim ) 한국화학공학회 1994 춘계학술발표회 Vol.- No.-

질산제조 플랜트 N2O 제거용 촉매기술: 적용위치별 기술옵션

김문현 ( Moon Hyeon Kim ) 한국환경과학회 2012 한국환경과학회지 Vol.21 No.1

A unit emission reduction of nitrous oxide (N2O) from anthropogenic sources is equivalent to a 310-unit CO2 emission reduction because the N2O has the global warming potential (GWP) of 310. This greatly promoted very active development and commercialization of catalysts to control N2O emissions from large-scale stationary sources, representatively nitric acid production plants, and numerous catalytic systems have been proposed for the N2O reduction to date and here designated to Options A to C with respect to in-duct-application scenarios. Whether or not these Options are suitable for N2O emissions control in nitric acid industries is primarily determined by positions of them being operated in nitric acid plants, which is mainly due to the difference in gas temperatures, compositions and pressures. The Option A being installed in the NH3 oxidation reactor requires catalysts that have very strong thermal stability and high selectivity, while the Option B technologies are operated between the NO2 absorption column and the gas expander and catalysts with medium thermal stability, good water tolerance and strong hydrothermal stability are applicable for this option. Catalysts for the Option C, that is positioned after the gas expander thereby having the lowest gas temperatures and pressure, should possess high deN2O performance and excellent water tolerance under such conditions. Consequently, each deN2O technology has different opportunities in nitric acid production plants and the best solution needs to be chosen considering the process requirements.

아디픽산 제조공정으로부터 발생되는 N2O에 대한 배출제어기술

김문현 ( Moon Hyeon Kim ) 한국환경과학회 2011 한국환경과학회지 Vol.20 No.6

Nitrous oxide (N2O) is one of six greenhouse gases listed up in the Kyoto Protocol, and it effects a strong global warming because of its much greater global warming potential (GWP), by 310 times over a 100-year time horizon, than CO2. Although such N2O emissions from both natural and anthropogenic sources occur, the latter can be controlled using suitable abatement technologies, depending on them, to reduce N2O below acceptable or feasible levels. This paper has extensively reviewed the anthropogenic N2O emission sources and their related compositions, and the state-of-the-art non-catalytic and catalytic technologies of the emissions controls available currently to representative, large N2O emission sources, such as adipic acid production plants. Challengeable approaches to this source are discussed to promote establishment of advanced N2O emission control technologies.

총설 : 화력발전소용 V2O5/TiO2계 촉매상에서 NH3-SCR 탈질반응으로부터의 N2O 생성

김문현 ( Moon Hyeon Kim ) 한국화학공학회 2013 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.51 No.2

V2O5/TiO2계 촉매상에서 NH3에 의한 NOx의 선택적환원은 310의 지구온난화지수를 갖는 N2O의 또 다른 인위적인 배출원이 될 수 있는 것으로 보고되고 있으므로, 본 총설은 화석연료를 연소시키는 화력발전소용 상기 촉매상에서 SCR 탈질반응 동안에 N2O 생성과 관계되는 주요 변수들의 유의성을 다루고자 한다. NH3-SCR 탈질반응에서 N2O 배출은 NH3 산화반응에 더하여 반응 중에 존재하는 NOx와 NH3 간의 부반응을 통해 일어나고. 이 부반응들의 정도는 SCR 촉 매의 활성성분인 V2O5의 함량과 조촉매의 종류(WO3와 MoO3), 반응온도, NO2/NOx 비율, 산소농도, 공간속도, 수분함 량, 열처리 등과 같은 유입가스 조건과 운전변수 및 화력발전소 현장에 설치된 상용 SCR 탈질공정에서 격은 촉매의 이력에 크게 의존한다. 상기의 모든 변수들이 탈질반응에서 N2O 생성과 관계된다고 할지라도, 몇몇 핵심변수들이 N2O 생성에 미치는 영향과 상용 SCR 공정에서 N2O 생성을 억제할 수 있는 방안이 고찰되었다. Selective catalytic reduction of NOx by NH3 (NH3-SCR) over V2O5/TiO2-based catalysts is recently reported to be an anthropogenic emitter of N2O that is a global warming gas with a global warming potential of 310. Therefore, this review will get a touch on significance of some parameters regarding N2O formation in the deNOxing reaction for fossil fuels-fired power plants applications. The N2O production in NH3-SCR reaction with such catalysts occurs via side reactions between NOx and NH3 in addition to NH3 oxidation, and the extent of these undesired reactions depends strongly on the loadings of V2O5 as a primary active component and the promoter as a secondary one (WO3 and MoO3) in the SCR catalysts, the feed and operating variables such as reaction temperature, NO2/NOx ratio, oxygen concentration, gas hourly space velocity, water content and thermal excursion, and the physical and chemical histories of the catalysts on site. Although all these parameters are associated with the N2O formation in deNOxing reaction, details of some of them have been discussed and a better way of suppressing the N2O production in commercial SCR plants has been proposed.

Pt/SiO_2 촉매상에서 H_2에 의한 저온 N_2O 제거반응

김문현 ( Moon Hyeon Kim ),김대환 ( Dae Hwan Kim ) 한국환경과학회 2013 한국환경과학회지 Vol.22 No.1

농업폐기물 소각에 따른 대기오염 실태 및 위해성 평가

김문현,양원호,Kim, Moon-Hyeon,Yang, Won-Ho 한국환경보건학회 2007 한국환경보건학회지 Vol.33 No.1

Waste policies with waste metering system and recycling in 1995 have contributed to the reduction of solid waste generation. Now rural areas as well as urban areas produce less amount of solid wastes in terms of per capita. However most policies in relation to waste issue have been concentrated in urban areas. Large portion of agricultural waste in rural region are being illegally treated such as open incineration or burned out on the road. In this study, we assessed the atmospheric air quality and health risk by illegal open incineration in rural region. In case of benzene level, worst concentration during illegal open incineration was 0.23 ppm and cancer risk by exposure was estimated to $2.29{\times}10^{-3}$.

금속-유기 골격계 다공성 흡착제의 이산화탄소 흡착성능과 압력순환흡착 공정 적용의 문제점

김문현(Moon Hyeon Kim),최상옥(Sang Ok Choi),추수태(Soo Tae Choo) 한국청정기술학회 2013 청정기술 Vol.19 No.4

본 논고에서는 가스 흡착·분리 산업에서 광범위하게 적용되고 있는 압력순환흡착(pressure swing adsorption, PSA) 기술의 전형적인 흡착조건인 15~40 ℃의 온도와 4~6 bar의 압력에서 금속-유기 골격체(metal-organic frameworks, MOF)와 제올라이트 이미다졸레이트 골격체(zeolite imidazolate frameworks, ZIF)의 CO₂ 흡착성능을 살펴보고 이들이 가지고 있는 장·단점을 분석해보고자 한다. CO₂는 H₂, CO, N₂ 및 CO₂와 같은 기체분자들에 비해 큰 분극률을 가지므로 동일한 세공크기라면 흡착제의 비표면적이 클수록 높은 흡착량을 보이며, CO₂의 분자크기(3.3 Å)보다 큰 세공으로 이루어진 흡착제라면 상기 흡착조건에서의 CO₂ 흡착성능은 세공크기에 크게 영향을 받는다. MOF와 ZIF의 CO₂ 흡착성능은 이들의 골격을 이루는 금속과 유기 링커의 종류, 세공크기, 비표면적, 흡착조건(온도와 압력) 등에 따라 달라질 수 있지만, 특히 흡착압력의 영향이 절대적이다. 다시 말하면, CO₂의 흡착압력이 비슷할 경우 MOF와 ZIF의 CO₂ 흡착량에 미치는 상기 인자들의 영향은 비교적 작다. 15 bar 이상의 CO₂ 흡착압력에서 이 흡착제들이 수 십 mmol/g의 흡착성능을 나타낸다고 할지라도, 전형적인 PSA 공정조건에서 이들의 CO₂ 흡착성능은 제올라이트, 활성탄과 같은 벤치마크 흡착제들의 성능과 유사하거나 오히려 낮을 뿐만 아니라, 이들의 가격은 벤치마크들에 비해 매우 높기 때문에 경제성 확보에 어려움이 있다. This review has shown the capability of MOFs and ZIFs materials to adsorb CO₂ under typical PSA temperatures and pressures. The usual operating conditions are adsorption temperatures of 15~40 ℃ and adsorption pressures of 4~6 bar based on numerous PSA processes which are widely employed in gases industry for adsorptive separation of CO₂. The extent of CO₂ adsorption on the microporous materials depends on the metal species and organic linkers existing in the frameworks. The pore size and the surface area, and the process variables are the key parameters to be associated with the efficiency of the adsorbents, particularly adsorption pressures if other variables are comparable each other. The MOFs and ZIFs materials require high pressures greater than 15 bar to yield significant CO₂ uptakes. They possess a CO₂ adsorption capacity which is very similar to or less than that of conventional benchmark adsorbents such as zeolites and activated carbons. Consequently, those materials have been much less cost-effective for adsorptive CO₂ separation to date because of very high production price and the absence of commercially-proven PSA processes using such new adsorbents.

MW급 석탄연소 배가스에서 탈질촉매시스템을 이용한 원소수은 산화 실증사례

김문현(Moon Hyeon Kim),응웬 티 프엉 타오(Thi Phuong Thao Nguyen) 한국청정기술학회 2021 청정기술 Vol.27 No.3

석탄화력발전소로부터 배출되는 질소산화물(NO + NO₂ = NOx)은 NH₃를 환원제로 사용하여 선택적으로 환원시키는 SCR(selective catalytic reduction) 탈질촉매시스템에서 효과적으로 제거될 수 있다. 이 SCR 촉매공정에서 원소수은을 산화시켜 후속공정에서 제거하기 위하여 수많은 산화촉매들이 제안되었으나 MW급 석탄연소시설이나 상업운전 중인 석탄발전소 탈질시스템에서 원소수은 산화성능을 실증한 사례들은 매우 드물다. 실배가스에서 수행한 실증연구들을 심층적으로 조사‧분석한 바는 기존 SCR 탈질촉매뿐 아니라 수은산화능을 향상시킨 신촉매의 원소수은 산화활성은 석탄연소, 실배가스 등의 특성에 따라 매우 복잡한 양상을 띤다는 점이다. 그럼에도 불구하고 석탄연소시설에 사용하는 원료탄, 탈질시스템과 실증조건이 원소수은 산화능에 가장 큰 영향을 미치는 핵심 요소이다. 특히, 원료탄에 함유된 할로겐 함량은 탈질촉매공정의 중요성을 넘어서는 것으로 보여진다. 석탄에 존재하는 대표적인 할로겐 성분은 Cl, Br과 F이고 이들 중에서 Cl이 지배적이며 다른 할로겐계처럼 염으로 존재하지만 석탄연소 과정에서 미량의 Cl₂와 함께 HCl로 전환된다. 이러한 HCl은 원소수은 산화에 있어서 강력한 산화제로 작용하지만 석탄마다 Cl 함량이 다르기 때문에 HCl 농도 또한 강하게 의존한다. Major anthropogenic emissions of elemental mercury (Hg<SUP>0</SUP>) occur from coal-fired power plants, and the emissions can be controlled successfully using NH₃-SCR (selective catalytic reduction) systems with catalysts. Although the catalysts can easily convert the gaseous mercury into Hg<SUP>2+</SUP> species, the reactions are greatly dependent on the flue gas constituents and SCR conditions. Numerous deNOxing catalysts have been proposed for considerable reduction in power plant mercury emissions; however, there are few studies to date of elemental mercury oxidation using SCR processes with MW- and full-scale coal-fired boilers. In these flue gas streams, the chemistry of the mercury oxidation is very complicated. Coal types, deNOxing catalytic systems, and operating conditions are critical in determining the extent of the oxidation. Of these parameters, halogen element levels in coals may become a key vehicle for obtaining better Hg<SUP>0</SUP> oxidation efficiency. Such halogens are Cl, Br, and F and the former one is predominant in coals. The chlorine exists in the form of salts and is transformed to gaseous HCl with a trace amount of Cl₂ during the course of coal combustion. The HCl acts as a very powerful promoter for high catalytic Hg<SUP>0</SUP> oxidation; however, this can be strongly dependent on the type of coal because of a wide variation in the chlorine contents of coal.